Heterogeneous networks (HetNets) are now being developed wherein cells of smaller size are embedded within the coverage area of larger Macro cells, primarily to provide increased capacity in targeted areas of data traffic concentration. Such heterogeneous networks try to exploit the spatial variations in user (and traffic) distribution to efficiently increase the overall capacity of the wireless network. Those smaller-sized cells are typically referred to as Pico Cells or Femto Cells, and for purposes of the description herein will generally be referred to as Femto Cells.
In 1×EVDO, when Femto Cells are embedded within the coverage area of a Macro cell, the Macro cell cannot always know or be able to find out the IP address of the Femto either for paging according to the A13 protocol or Femto-to-Macro session transfer without additional changes to the air interface for the access terminal (AT) (sometimes referred to as the mobile terminal). Known solutions will not work for current ATs. Additionally, the ATs could still be indiscriminately transferring their sessions between the Macro and Femto cells (and vice-versa), which would incur a large increase in processor occupancy of the Macro system.